document.write( "<A HREF=/cgi-bin/jump-to-question.mpl?question=111370>Question 111370</A>: <I><SPAN STYLE=\"word-break: break-all;\"> Given 3 sides of a rectangular fence have a perimeter of 80 feet.  Find the largest possible area. </SPAN>\n" );
document.write( "</I><HR><TABLE width=100%><TR><TD><B><A HREF=http://www.algebra.com/>Algebra.Com's</A> Answer #81201 by </B><A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><B>jim_thompson5910(35256)</B></A><img src=\"/images/stars/stars-13.gif\" alt=\"\" >&nbsp;<A HREF=/tutors/aboutme.mpl?userid=jim_thompson5910><IMG SRC=http://www.algebra.com/images/aboutme-small.gif BORDER=0 alt=\"About Me\" VALIGN=MIDDLE></A>&nbsp;<IMG SRC=http://www.algebra.com/images/nopicture.jpg><BR>You can <A HREF=\"/cgi-bin/embed-solution.mpl?show=1&solution=81201\">put this solution on YOUR website!</A><BR><SPAN STYLE=\"word-break: break-all;\"> The formula for the perimeter of rectangle is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=2L%2B2W ALIGN=MIDDLE  ALT=\"P=2L%2B2W\"   DISABLED_style= \"max-width:90%; height:auto;\" >, but since we have 3 sides, the formula becomes <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=P=L%2B2W ALIGN=MIDDLE  ALT=\"P=L%2B2W\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now set the perimeter P equal to 80\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=80=L%2B2W ALIGN=MIDDLE  ALT=\"80=L%2B2W\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now solve for L\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=L=80-2W ALIGN=MIDDLE  ALT=\"L=80-2W\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now the area of a rectangle is <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=L%2AW ALIGN=MIDDLE  ALT=\"A=L%2AW\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=%2880-2W%29%2AW ALIGN=MIDDLE  ALT=\"A=%2880-2W%29%2AW\"   DISABLED_style= \"max-width:90%; height:auto;\" > Plug in <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=L=80-2W ALIGN=MIDDLE  ALT=\"L=80-2W\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "Now plot <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=A=%2880-2W%29%2AW ALIGN=MIDDLE  ALT=\"A=%2880-2W%29%2AW\"   DISABLED_style= \"max-width:90%; height:auto;\" > as a function of x. Simply change A to y and w to x to get <IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=y=%2880-2x%29%2Ax ALIGN=MIDDLE  ALT=\"y=%2880-2x%29%2Ax\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "<IMG STYLE=\"max-width:80%;\" SRC=/cgi-bin/plot-formula.mpl?expression=+graph%28+500%2C+500%2C+-50%2C+50%2C+-10%2C+800%2C+%2880-2x%29%2Ax%29+ ALIGN=MIDDLE  ALT=\"+graph%28+500%2C+500%2C+-50%2C+50%2C+-10%2C+800%2C+%2880-2x%29%2Ax%29+\"   DISABLED_style= \"max-width:90%; height:auto;\" >\r<BR>\n" );
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document.write( "From the graph we can see that the max is at x=20, which means y=800. So when the width is 20 ft the area is maxed out at 800 square feet </SPAN>\n" );
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